The invention relates to an apparatus for heating heat-accumulating food-warmer plates. The apparatus comprises a housing into which a plurality of food-warmer plates may be slid through separate slots in the housing wall. An electrical heating device is disposed in the housing.
An apparatus of this general type is known in the prior art, e.g., Swiss Pat. No. 323,543. In the known apparatus the electrical heating device is intended to heat the entire interior space of the housing to a final or predetermined temperature. The food-warmer plates in the housing are heated together, and they may be individually removed and returned as requirements of use dictate.
If only a few of the heated warmer plates are needed, the energy consumption of the known apparatus is relatively high, because it is always necessary to heat the entire housing and all the warmer plates present therein, including the plates not needed.
A different type of known apparatus for heating food-warmer plates avoids this drawback, in that each food-warmer plate has its own built-in electrical heating element, and the housing in which a plurality of such plates may be inserted does not comprise a heating device but merely has electrical terminals to which the food-warmer plates may be connected e.g., Fr. Pat. No. 2,286,630. However, plates containing electrical devices and connecting terminals for these devices, are not generally suitable, at least not for commercial use, e.g. in restaurants, because they cannot be properly cleaned in a simple fashion. In the cleaning process, special attention must be paid to the electrical devices and connecting contacts. There is always the hazard of damage to the electrical devices and/or contacts due to careless cleaning or washing, which may lead to short circuits or life-threatening unintentional grounding.
Thus it is the object of the present invention to provide an apparatus for warming plates, wherein the electrical heating device is disposed within the housing and the food-warmer plates do not contain any electrical parts so as to avoid the disadvantage of high energy consumption and to enable energy savings.
The object is achieved according to the invention in that the heating device is comprised of heating elements which may be switched on and off individually, such that each heating element is associated with one of the food-warmer plates in the housing, so as to heat that particular food-warmer plate.
In this way, each of the food-warmer plates of the present device can be heated separately. In each use situation, one can then select for heating only that number of plates which will actually be needed. It is no longer necessary to heat the entire set of plates when only two or three will be needed.
Preferably, each heating element may also be switched off by a thermostat switch controlled by a temperature sensor disposed so as to determine the temperature of the respective food-warmer plate, whereby the thermostat switch may switch off the heating element as soon as the warmer plate reaches a predetermined or final temperature. During the time the plate is being heated to the predetermined temperature, the temperature between the plate and the heating element may be higher than the final temperature, in order to enable rapid heating of the plate. In contrast, to the above-described known apparatus, the temperature maintained within the housing is identical to the final temperature of the plates, and the plates approach the predetermined or final temperature asymptotically.